XRD analysis determined crystal cage occupying number n of carbon anion substituted mayenite-type cage compound C12A7: NC

Abstract

In this study, a series of samples of C12A7 derivative was prepared by high temperature sintering in a sealed graphite crucible. The theoretical model of C12A7 derivatives with different carbon occupation numbers was established. The X-ray diffraction (XRD) theoretical calculation was carried out. The conjecture was verified to a certain extent through the comparison of the theoretical calculation of XRD with the experimental results. According to the calculation results, it was found that the XRD patterns of C12A7 and its derivatives changed regularly with the change in the occupation number in the crystal cage. Under the condition that the types of vacancy atoms remained unchanged, the more vacancy atoms occupied in C12A7 crystal, the higher the peak at 2θ = 33.35° in the diffraction pattern. It was also found that the higher the atomic number of vacancy atoms in C12A7 crystal, the higher the peak at 2θ = 33.35° in the diffraction pattern. The carbon occupation number of samples at different experimental temperatures was deduced. The results showed that the carbon occupancy of the samples prepared at 990, 1,353 and 1,680°C were 11, 4 and 8, respectively.